Mitogen-activated protein kinases (MAP kinase) mediate proliferation or induce differentiation or apoptosis by phosphorylation of cytosolic and nuclear targets. Dual- specificity phosphatases (DSPTP) negatively regulate MAP kinases by dephosphorylating thre-onine and tyrosine residues necessary for MAP kinase activity. The hypothesis to be tested is that adenoviral-mediated gene transfer (AMGT) of DSPTP will negatively regulate MAP kinase signaling pathways in a substrate-specific manner. Furthermore, glomerulonephritic rats will be infected with adenovirus harboring a smooth muscle (SMC) and mesangial cell (MC) specific promoter to test the hypothesis that expression of a LacZ reporter gene is limited to SMC and MC in vivo as a first step toward targeted delivery of DSPTP. Specific Aim number 1 will determine the specificity of AMGT of DSPTP to negatively regulate MAP kinases. Specific Aim number 2 will determine the effects of AMGT of DSPTP on expression of the immediate early genes, c-fos, c-jun and PGHS2. These specific aims will be tested by measuring the effects of DSPTP on MAP kinase activity and on MAP kinase-induced induction of immediate early genes using primary cultures of SMC and MC transduced with DSPTP and stimulated with endothelin or IL-6. Specific Aim number 3 will determine specific targeting of SMC and MC in vivo. The long term goal of the applicant is to develop AMGT strategies for treatment of proliferative cardiorenal disease.